224 



Many more comparative studies Avill be required before eath step in 

 tlie process can be described in detail. All the conditions necessary for 

 the formation of a tamarack swamp can not now be stated, although two 

 are apparent (1) a relatively deep lake; (2) the destruction of this lake by 

 plant deposition, for this alone can produce the proper substratum for 

 the introduction of the tamarack. 



A list of the orders of plants and the species in each found in the 

 Leesburg Swamp: 



1. Nyjiph.i;aceje. 



Nuphar advena. 



2. Sarraceniace.^. 



Sarracenia purpurea. 



3. Geraniaceje. 



finpatiens hiflora. 



4. Ilicixe.e. 



Ilex montlcola. 



5. Sapindace-i:. 



Acer rubrum. 



n. Anacardiace^^. 



RJlus venenata. 



7. Rosace.e. 



Spirea saliclfolia, S. tomentosa, Rosa Carolina, Poleniilla Canadensis, P. 

 argentea, Rubus hispidu^, Agrimonia paniflora. Primus Americana, 

 Pyrus coronana. 



8... Crassulace.e. 



Penthorum sedoides. 



9. Droserace^. 



Drosera rotundifolia, D. intermedia. 



10. OXAGRACE.E. 



Epilobium sfrictum. 



11. CORXACE^. 



Cornus Canadensis, C. Horida, C. sericea, C. stolonifera, C. paniculuta, 

 Nyssa sylvatica. 



